Lixiviation of a silver ore by the Russell process

The purpose of this investigation was to determine by a series of experiments, the action of the Russell solution on a particular ore; and to determine the best size to crush to, the strength of the solution to use, the temperature most suited, and the length of time for best extraction, and finally to come to a conclusion whether or not the ore was suited to this Process --page 1

Historical and critical examination of the notion of human-divine paradox as typified in two images from Late Quattrocento Italy

During the Renaissance there were developments in thought and practice within both artistic and academic fields. These movements, being intertwined with theology, created an exciting context for the re-interpretation of such concepts as the Trinity, Christ’s humanity, and the limits of representation. The aim of this thesis is to analyse two images which illustrate these rationalizations of the Doctrine of the Trinity and particularly the human-divine paradox, at the height of Renaissance ingenuity. This thesis will explore the interaction between the historical, theological, cultural and philosophical frameworks as they influence the composition of High Renaissance art. Conversely, this investigation will examine how these disciplines’ are fuelled by the artworks themselves. Within this artistic development of the Trinity, the most startling evolution is found in the interplay between humanity and divinity as seen in the three persons of the Trinity. This paradox provides valuable information concerning the bias of the artist and of the period. However, it also raises questions concerning the extent of theological orthodoxy, liturgical integrity, and symbolic accuracy which need to be addressed by the observer. It is in considering these questions that I hope to be able to express some of the factors which were important to the theological world of the 15th century and which are still important to 21st century understanding of the nature of the Trinity

Differential population synthesis of 17 early-type galaxy nuclei in the Fornax cluster

Flux calibrated spectra have been obtained of the nuclei of 12 Elliptical and 5 Lenticular galaxies in the FORNAX cluster, at a resolution of 10 - 20 A and in the wavelength range 0.36 to 0.72 micron. The observations have been extended to a long wavelength limit of 0.88 or 1.0 micron for 12 of the galaxies. The galaxies observed cover a 6 magnitude range of absolute magnitude and define the form and intrinsic width of the cluster colour-magnitude relation well. The galaxy spectra have been synthesised with a flux library of 48 synthesis standard spectra, compiled from spectrophotometry of ~200 stars in the wavelength range 0.36 to 1.0 micron at a resolution of 15 A. The stars observed cover a complete solar abundance sequence of all spectral types and luminosity classes, with additional metal-weak and metal-rich G-K giant branch sequences. The results presented here confirm that population synthesis of several galaxies covering a large range of absolute magnitude in one cluster permits good differential comparison of the mean galactic metallicities and ages associated with the main sequence turnoff group. The major conclusions are : 1) The metallicity results confirm the well known trend of decreasing mean metallicity with decreasing galactic luminosity. A metallicity gradient in [Fe/H] of at least 0.16 dex per magnitude is indicated over the 6 magnitude range of absolute magnitudes studied here. The brightest ellipticals NGC1399 and NGC1404 are 2 to 3 times more metal-rich than solar. The trend of mean metallicity with luminosity is the principle factor determining the slope of the cluster CM relation. 2) The ages associated with the main sequence turnoff groups are generally quite young (6 to 10 Gyr). This implies that substantial star formation has occurred in all early-type galaxies for about 8-10 Gyr after the epoch of globular cluster formation. The only possible trend of turnoff age with luminosity is towards younger ages (more extended star formation) in brighter ellipticals. 3) The turnoff ages of the lenticulars are significantly older (> 3 Gyr) than those of ellipticals of the same absolute magnitude, implying that star formation terminated earlier in lenticular systems. The mean metallicity of the lenticulars is also lower than that of ellipticals of the same absolute magnitude. 4) Three bright ellipticals (NGC’s 1404, 1399 and 1379) show strong evidence for a significant blue light contribution due to late 0 dwarfs, implying some ongoing star formation in at least these systems. Syntheses of other early-type galaxies also favour some 0-B dwarf contribution, but these galaxies can be equally well fitted with an enhanced metal-weak G-K giant contribution and some horizontal branch starlight. A significant 0 dwarf contribution (10 % at U) is consistent with a strong turnup in the uv flux below 1800 A, whereas a purely horizontal branch contribution would provide a ~flat uv continuum. Hot dying stars can not be present in sufficient numbers to contribute significantly to the uv flux in any early-type galaxy. UV bright stars could provide a significant fraction of the uv flux in the fainter, metal-weak galaxies. 5) There is a weak correlation between the percentage light contribution due to OB dwarf stellar groups, and the colour residuals from the mean (U36-V) vs. V nuclear colour-magnitude relation. Variations in the contribution due to recently formed OB dwarfs could account for a significant fraction of the intrinsic width in (U-V) of the cluster CM relation. 6) The faintest ellipticals studied here have absolute magnitudes similar to that of M32. The faintest elliptical 0333-36 is isolated from other galaxies and is clearly very metal-weak with [Fe/H] < -0.6. Star formation ceased at least 8 Gyr ago in 0333-36. The faint elliptical JJ79 is situated in the cluster core close to several other early-type galaxies. The metallicity of JJ79 is solar or greater, and this galaxy shows strong indications that substantial star formation activity occurred as recently as 3 Gyr ago. Relatively high (solar) metallicity and indications of recent star formation in low luminosity ellipticals such as M32 and JJ79 are probably consequences of tidal interactions with massive companions. The population synthesis technique can also give galactic mass to light ratios which are independent of distance. The results show that detailed population syntheses of near infra-red spectra from 0.7 to 1.0 micron enable only upper limits to be reliably calculated for the mass to light ratios of early-type galaxies. The conclusions regarding galactic mass to light ratios are : 7) The measured near infra-red spectra of galaxies can be well fitted by several combinations of M dwarf to M giant contribution ratios, resulting in M/Lv ratios in the range 1 to 13 for most early-type galaxies. The Na I doublet feature at 8190 A does not provide sufficient discrimination between M dwarfs and M giants to determine more precise values of M/Lv, although the fairly low measured equivalent widths clearly excludes M/Lv values greater than 20. Good quality spectra of the Wing-Ford (FeH) band at 9910 A may enable more reliable estimates of mass to light ratios to be derived from synthesis techniques. 8) Upper limits to M/Lv ratios calculated from synthesis fits conform well with M/Lv ratios calculated from nuclear velocity dispersion measurements. There is no reliable evidence for hidden mass in the nuclei of early-type galaxies of any luminosity. The dynamical estimates are consistent with galaxy M/L^ values of about 5 (M/LB ~ 7) , independent of absolute magnitude

Community assembly and stability in the root microbiota during early plant development

Little is known about how community composition in the plant microbiome is affected by events in the life of a plant. For example, when the plant is exposed to soil, microbial communities may be an important factor in root community assembly. We conducted two experiments asking whether the composition of the root microbiota in mature plants could be determined by either the timing of root exposure to microbial communities or priority effects by early colonizing microbes. Timing of microbial exposure was manipulated through an inoculation experiment, where plants of different ages were exposed to a common soil inoculum. Priority effects were manipulated by challenging roots with established microbiota with an exogenous microbial community. Results show that even plants with existing microbial root communities were able to acquire new microbial associates, but that timing of soil exposure affected root microbiota composition for both bacterial and fungal communities in mature plants. Plants already colonized were only receptive to colonizers at 1 week post-germination. Our study shows that the timing of soil exposure in the early life stages of a plant is important for the development of the root microbiota in mature plants

Understanding Humanitarian Supply Chain Logistics with Systems Dynamics Modeling

Purpose – We explore the short-term humanitarian response to a natural disaster that prompts a rapid influx of relief supplies to the area affected by the disaster, aiming to understand the dynamics of systemic processes that apply to humanitarian supply chain logistics. Design/methodology/approach – We use system dynamics to simulate the disaster relief supply chain elements of humanitarian response. System dynamics is a well-established simulation method for analyzing complex social systems that include feedback. We used it because the timing and coordination of, and feedback loops among, events in humanitarian response incorporate a delay structure that can be modeled effectively using system dynamics. Findings – Of all the stocks in our model of the Humanitarian Stock Management System, the most important was the Cumulative Food distributed to disaster victims. In all of our simulation runs, victims eventually got all the food they needed, but at varying speeds (fast in the base run, slow in runs where repair of infrastructure was slow). However, the most problematic stock was the amount of Food in the Central Warehouse. In almost all the runs, that stock contained an excess of food (which is very common in such situations), resulting in waste and inefficiency. This problem was worst when the agency panicked at the outset and doubled its estimate of needed food, and when, as is often true, the agency received too many in-kind donations of food. The most interesting finding was that “managing” donations led to the best overall performance--low waste, good relief for victims. Practical implications – We offer a number of policy recommendations, including the need to avoid early bias, to repair infrastructure as quickly as possible, to develop better methods for keeping track of inventories and supplies on the way, and striking a balance between encouraging and dampening donations. Originality/value – This study focuses on understanding the short-term dynamics of the logistics of a humanitarian response, using a system dynamics approach. There have been only two other studies applying system dynamics to humanitarian assistance. One was operational and focused on long-term dynamics (often called “development,” as opposed to “response”) and the other was abstract and focused on those same longer-term dynamics. While these studies have produced meaningful insight, our study is unique in that we have applied an operational approach to a short, or “crisis response,” time horizon

Below-ground biotic interactions moderated the postglacial range dynamics of trees

Tree range shifts during geohistorical global change events provide a useful real-world model for how future changes in forest biomes may proceed. In North America, during the last deglaciation, the distributions of tree taxa varied significantly in the rate and direction of their responses for reasons that remain unclear. Local-scale processes such as establishment, growth, and resilience to environmental stress ultimately influence range dynamics. Despite the fact that interactions between trees and soil biota are known to influence local-scale processes profoundly, evidence linking belowground interactions to distribution dynamics remains scarce. • We evaluated climate velocity and plant traits related to dispersal, environmental tolerance, and belowground symbioses, as potential predictors of the geohistorical rates of expansion and contraction of the core distributions of tree genera between 16-7kaBP. • The receptivity of host genera towards ectomycorrhizal fungi was strongly supported as a positive predictor of poleward rates of distribution expansion, and seed mass was supported as a negative predictor. Climate velocity gained support as a positive predictor of rates of distribution contraction, but not expansion. • Our findings indicate that understanding how tree distributions, and thus forest ecosystems, respond to climate change requires the simultaneous consideration of traits, biotic interactions, and abiotic forcing

Mismatched prenatal and postnatal maternal depressive symptoms and child behaviours: a sex-dependent role for NR3C1 DNA methylation in the Wirral Child Health and Development Study

Evolutionary hypotheses predict that male fetuses are more vulnerable to poor maternal conditions (Sex-biased Maternal Investment), but female fetuses are at greater risk of glucocorticoid-mediated disorders where there is a mismatch between fetal and postnatal environments (Predictive Adaptive Response). Self-reported prenatal and postnatal depression and maternal report of child anxious-depressed symptoms at 2.5, 3.5 and 5.0 years were obtained from an ‘extensive’ sample of first-time mothers (N = 794). Salivary NR3C1 1-F promoter methylation was assayed at 14 months in an ‘intensive’ subsample (n = 176) and stratified by psychosocial risk. Generalised structural equation models were fitted and estimated by maximum likelihood to allow the inclusion of participants from both intensive and extensive samples. Postnatal depression was associated with NR3C1 methylation and anxious-depressed symptoms in daughters of mothers with low prenatal depression (prenatal-postnatal depression interaction for methylation, p 0.001; for child symptoms, p = 0.011). In girls, NR3C1 methylation mediated the association between maternal depression and child anxious-depressed symptoms. The effects were greater in girls than boys: the test of sex differences in the effect of the prenatal-postnatal depression interaction on both outcomes gave X2 (2) = 5.95 (p = 0.051). This was the first human study to show that epigenetic and early behavioural outcomes may arise through different mechanisms in males and females

Transduction of Non-Small Cell Lung Cancer Cells by Adenoviral and Retroviral Vectors

Gene transfer into a panel of non-small cell lung cancer (NSCLC) cells by adenoviral (Ad) and retroviral (RV) vectors was studied. Indexed to multiplicity of infection (MOI), Ad vectors transduce squamous, adenosquamous, and malignant mesothelioma cells with greater efficiency than large cells or adenocarcinoma cells. Transduction-sensitive cells bind the Ad vector with specificity for the Ad fiber knob, and internalize vector efficiently. Transduction-refractory cells bind and internalize vector by less efficient pathways. Like Ad vectors, there is heterogeneity in RV transduction efficiencies of different NSCLC subtypes. With respect to the most common cell type metastatic to the pleural space (adenocarcinoma), amphotropic retroviral vectors transduce cells of this subtype more efficiently (at a lower MOI) than Ad. RV transduction is not solely dependent on cellular replication, and both permissive and refractory cell lines express the mRNA for the amphotropic RV receptor. These observations suggest that neither Ad nor RV vectors will suffice a priori as the optimal gene transfer vehicle, and successful gene therapy of lung cancer may require tumor-specific or patient-specific vectors

Human factors in clinical handover: development and testing of a ‘handover performance tool' for doctors' shift handovers

Objective To develop and test a handover performance tool (HPT) able to help clinicians to systematically assess the quality and safety of shift handovers. Design The study used a mixed methods approach. In the development phase of the tool, a review of the literature and a Delphi process were conducted to sample five generic non-technical skills: communication, teamwork, leadership, situation awareness and task management. Validity and reliability of the HPT were evaluated through direct observation and during simulated handover video sessions. Setting This study was conducted in the Paediatrics, Obstetrics and Gynaecology wards of a UK district hospital. Participants Thirty human factor experts participated in the development phase; 62 doctors from various disciplines were asked to validate the tool. Main Outcome Measures Item development, HPT validity and reliability. Results The tool developed consisted of 25 items. Communication, teamwork and situation awareness explained, respectively, 55.5, 47.2 and 39.6% of the variance in doctors rating of quality. Internal consistency and inter-rater reliability of the HPT were good (Cronbach's alpha = 0.77 and intra-class correlation = 0.817). Conclusions Communication determined the majority of handover quality. Teamwork and situation awareness also provided an independent contribution to the overall quality rating. The HPT has demonstrated good validity and reliability providing evidence that it can be easily used by raters with different backgrounds and in several clinical settings. The HPT could be utilized to assess doctors' handover quality systematically, as well as teaching tool in medical schools or in continuing professional development programmes for self-reflective practic